utils/nfsd/nfssvc.c

   1 /*
   2  * utils/nfsd/nfssvc.c
   3  *
   4  * Run an NFS daemon.
   5  *
   6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #ifdef HAVE_CONFIG_H
  10 #include <config.h>
  11 #endif
  12
  13 #include <sys/types.h>
  14 #include <sys/socket.h>
  15 #include <netdb.h>
  16 #include <netinet/in.h>
  17 #include <arpa/inet.h>
  18 #include <unistd.h>
  19 #include <fcntl.h>
  20 #include <errno.h>
  21
  22 #include "nfslib.h"
  23 #include "xlog.h"
  24
  25 #define NFSD_PORTS_FILE     "/proc/fs/nfsd/portlist"
  26 #define NFSD_VERS_FILE    "/proc/fs/nfsd/versions"
  27 #define NFSD_THREAD_FILE  "/proc/fs/nfsd/threads"
  28
  29 /*
  30  * declaring a common static scratch buffer here keeps us from having to
  31  * continually thrash the stack. The value of 128 bytes here is really just a
  32  * SWAG and can be increased if necessary. It ought to be enough for the
  33  * routines below however.
  34  */
  35 char buf[128];
  36
  37 /*
  38  * Are there already sockets configured? If not, then it is safe to try to
  39  * open some and pass them through.
  40  *
  41  * Note: If the user explicitly asked for 'udp', then we should probably check
  42  * if that is open, and should open it if not. However we don't yet. All
  43  * sockets have to be opened when the first daemon is started.
  44  */
  45 int
  46 nfssvc_inuse(void)
  47 {
  48         int fd, n;
  49
  50         fd = open(NFSD_PORTS_FILE, O_RDONLY);
  51
  52         /* problem opening file, assume that nothing is configured */
  53         if (fd < 0)
  54                 return 0;
  55
  56         n = read(fd, buf, sizeof(buf));
  57         close(fd);
  58
  59         xlog(D_GENERAL, "knfsd is currently %s", (n > 0) ? "up" : "down");
  60
  61         return (n > 0);
  62 }
  63
  64 static int
  65 nfssvc_setfds(const struct addrinfo *hints, const char *node, const char *port)
  66 {
  67         int fd, on = 1, fac = L_ERROR;
  68         int sockfd = -1, rc = 0;
  69         struct addrinfo *addrhead = NULL, *addr;
  70         char *proto, *family;
  71
  72         /*
  73          * if file can't be opened, then assume that it's not available and
  74          * that the caller should just fall back to the old nfsctl interface
  75          */
  76         fd = open(NFSD_PORTS_FILE, O_WRONLY);
  77         if (fd < 0)
  78                 return 0;
  79
  80         switch(hints->ai_family) {
  81         case AF_INET:
  82                 family = "inet";
  83                 break;
  84         default:
  85                 xlog(L_ERROR, "Unknown address family specified: %d\n",
  86                                 hints->ai_family);
  87                 rc = EAFNOSUPPORT;
  88                 goto error;
  89         }
  90
  91         rc = getaddrinfo(node, port, hints, &addrhead);
  92         if (rc == EAI_NONAME && !strcmp(port, "nfs")) {
  93                 snprintf(buf, sizeof(buf), "%d", NFS_PORT);
  94                 rc = getaddrinfo(node, buf, hints, &addrhead);
  95         }
  96
  97         if (rc != 0) {
  98                 xlog(L_ERROR, "unable to resolve %s:%s to %s address: "
  99                                 "%s", node ? node : "ANYADDR", port, family,
 100                                 rc == EAI_SYSTEM ? strerror(errno) :
 101                                         gai_strerror(rc));
 102                 goto error;
 103         }
 104
 105         addr = addrhead;
 106         while(addr) {
 107                 /* skip non-TCP / non-UDP sockets */
 108                 switch(addr->ai_protocol) {
 109                 case IPPROTO_UDP:
 110                         proto = "UDP";
 111                         break;
 112                 case IPPROTO_TCP:
 113                         proto = "TCP";
 114                         break;
 115                 default:
 116                         addr = addr->ai_next;
 117                         continue;
 118                 }
 119
 120                 xlog(D_GENERAL, "Creating %s %s socket.", family, proto);
 121
 122                 /* open socket and prepare to hand it off to kernel */
 123                 sockfd = socket(addr->ai_family, addr->ai_socktype,
 124                                 addr->ai_protocol);
 125                 if (sockfd < 0) {
 126                         xlog(L_ERROR, "unable to create %s %s socket: "
 127                                 "errno %d (%m)", family, proto, errno);
 128                         rc = errno;
 129                         goto error;
 130                 }
 131                 if (addr->ai_protocol == IPPROTO_TCP &&
 132                     setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on))) {
 133                         xlog(L_ERROR, "unable to set SO_REUSEADDR on %s "
 134                                 "socket: errno %d (%m)", family, errno);
 135                         rc = errno;
 136                         goto error;
 137                 }
 138                 if (bind(sockfd, addr->ai_addr, addr->ai_addrlen)) {
 139                         xlog(L_ERROR, "unable to bind %s %s socket: "
 140                                 "errno %d (%m)", family, proto, errno);
 141                         rc = errno;
 142                         goto error;
 143                 }
 144                 if (addr->ai_protocol == IPPROTO_TCP && listen(sockfd, 64)) {
 145                         xlog(L_ERROR, "unable to create listening socket: "
 146                                 "errno %d (%m)", errno);
 147                         rc = errno;
 148                         goto error;
 149                 }
 150
 151                 if (fd < 0)
 152                         fd = open(NFSD_PORTS_FILE, O_WRONLY);
 153
 154                 if (fd < 0) {
 155                         xlog(L_ERROR, "couldn't open ports file: errno "
 156                                       "%d (%m)", errno);
 157                         goto error;
 158                 }
 159
 160                 snprintf(buf, sizeof(buf), "%d\n", sockfd);
 161                 if (write(fd, buf, strlen(buf)) != strlen(buf)) {
 162                         /*
 163                          * this error may be common on older kernels that don't
 164                          * support IPv6, so turn into a debug message.
 165                          */
 166                         if (errno == EAFNOSUPPORT)
 167                                 fac = D_ALL;
 168                         xlog(fac, "writing fd to kernel failed: errno %d (%m)",
 169                                   errno);
 170                         rc = errno;
 171                         goto error;
 172                 }
 173                 close(fd);
 174                 close(sockfd);
 175                 sockfd = fd = -1;
 176                 addr = addr->ai_next;
 177         }
 178 error:
 179         if (fd >= 0)
 180                 close(fd);
 181         if (sockfd >= 0)
 182                 close(sockfd);
 183         if (addrhead)
 184                 freeaddrinfo(addrhead);
 185         return rc;
 186 }
 187
 188 int
 189 nfssvc_set_sockets(const int family, const unsigned int protobits,
 190                    const char *host, const char *port)
 191 {
 192         struct addrinfo hints = { .ai_flags = AI_PASSIVE | AI_ADDRCONFIG };
 193
 194         hints.ai_family = family;
 195
 196         if (!NFSCTL_ANYPROTO(protobits))
 197                 return EPROTOTYPE;
 198         else if (!NFSCTL_UDPISSET(protobits))
 199                 hints.ai_protocol = IPPROTO_TCP;
 200         else if (!NFSCTL_TCPISSET(protobits))
 201                 hints.ai_protocol = IPPROTO_UDP;
 202
 203         return nfssvc_setfds(&hints, host, port);
 204 }
 205
 206 void
 207 nfssvc_setvers(unsigned int ctlbits, int minorvers4)
 208 {
 209         int fd, n, off;
 210         char *ptr;
 211
 212         ptr = buf;
 213         off = 0;
 214         fd = open(NFSD_VERS_FILE, O_WRONLY);
 215         if (fd < 0)
 216                 return;
 217
 218         for (n = NFSD_MINVERS; n <= NFSD_MAXVERS; n++) {
 219                 if (NFSCTL_VERISSET(ctlbits, n))
 220                     off += snprintf(ptr+off, sizeof(buf) - off, "+%d ", n);
 221                 else
 222                     off += snprintf(ptr+off, sizeof(buf) - off, "-%d ", n);
 223         }
 224         n = minorvers4 >= 0 ? minorvers4 : -minorvers4;
 225         if (n >= NFSD_MINMINORVERS4 && n <= NFSD_MAXMINORVERS4)
 226                     off += snprintf(ptr+off, sizeof(buf) - off, "%c4.%d",
 227                                     minorvers4 > 0 ? '+' : '-',
 228                                     n);
 229         xlog(D_GENERAL, "Writing version string to kernel: %s", buf);
 230         snprintf(ptr+off, sizeof(buf) - off, "\n");
 231         if (write(fd, buf, strlen(buf)) != strlen(buf))
 232                 xlog(L_ERROR, "Setting version failed: errno %d (%m)", errno);
 233
 234         close(fd);
 235
 236         return;
 237 }
 238
 239 int
 240 nfssvc_threads(unsigned short port, const int nrservs)
 241 {
 242         struct nfsctl_arg       arg;
 243         struct servent *ent;
 244         ssize_t n;
 245         int fd;
 246
 247         fd = open(NFSD_THREAD_FILE, O_WRONLY);
 248         if (fd < 0)
 249                 fd = open("/proc/fs/nfs/threads", O_WRONLY);
 250         if (fd >= 0) {
 251                 /* 2.5+ kernel with nfsd filesystem mounted.
 252                  * Just write the number of threads.
 253                  */
 254                 snprintf(buf, sizeof(buf), "%d\n", nrservs);
 255                 n = write(fd, buf, strlen(buf));
 256                 close(fd);
 257                 if (n != strlen(buf))
 258                         return -1;
 259                 else
 260                         return 0;
 261         }
 262
 263         if (!port) {
 264                 ent = getservbyname("nfs", "udp");
 265                 if (ent != NULL)
 266                         port = ntohs(ent->s_port);
 267                 else
 268                         port = NFS_PORT;
 269         }
 270
 271         arg.ca_version = NFSCTL_VERSION;
 272         arg.ca_svc.svc_nthreads = nrservs;
 273         arg.ca_svc.svc_port = port;
 274         return nfsctl(NFSCTL_SVC, &arg, NULL);
 275 }